Windup roll drive



Sept. 19, 1961 E. w. CLEM 3,000,584

WINDUP ROLL DRIVE Filed July 29. 1957 s Sheets-Sheet 1 INVENTOR [ATTORNEYS Sept. 19, 1961 E. w. CLEM 3,000,584

' WINDUP ROLL DRIVE Filed July 29. 1957' :s Sheets-Sheet 2 INVENTOR Evererr W. Clem ATTORNEYS BY fl aw Amp M 3 Sept. 19, 1961 NNNNNN OR 3,000,584 WINDUP ROLL DRIVE Everett W. Clem, Shrewsbnry, Mass, assignor to Rice Barton Corporation, Worcester, Mass, a corporation of Massachusetts Filed July 29, 1957, Ser. No. 674,857 4 Claims. (Cl. 242--66) This invention relates to winding and unwinding mechanisms, and, more particularly, to a mechanism for winding up large rolls of web material such as paper to a predetermined hardness and density.

It is well known that in order to produce a properly wound roll of paper, highly accurate tension control must be maintained on the web during the entire winding operation. In one of the more effective approaches to such tension control, the web roll is substantially freely supported on a pair of winding rolls, one which is driven at a speed greater than the other. The winding rolls thereby impart rotary motion to the web roll causing successive layers of web to be wrapped thereabout, and as a result of the speed difierential between the winding rolls each successive layer is applied under predetermined tension.

This approach is sound in theory but in practice certain deficiencies become apparent as the web roll increases in weight during the winding operation. If power is transmitted to the winding rolls through a non-positive (e.g. a

clutch or belt) drive, the increasing load on the rolls often causes slippage in the drive and the relative speed differential between the rolls disappears along with most all of the effective web tension control. On the other hand, it because of a direct positive gear or chain drive between the winding rolls the speed differential ismaintained at constant value, the desired characteristics may not be obtained; e.g. if the web is wound too tightly as the roll increases in size and may well rupture subsequently during storage or handling of the roll.

Therefore, it is well recognized that by some method the speed differential between the winding rolls must be steadily diminished as the web roll grows larger, but at the same time diminution of the differential must positively be uniformly and continuously controlled. It has been suggested to incorporate a variable speed transmission directly into the drive of one of the winding rolls, but the results heretofore have not been entirely satisfactory. Mechanical or electro-mechanical clutches on one or both winder roll shafts have also been proposed as diiferential speed controls, but they too have not been entirely satisfactory in view of the great amount of power wasted thereby. Differential gear units have been adopted to divide the-rotary power of the driving motor between the two winding rolls, but clutches or brakes are still required on the winding rolls of such apparatus to control the speed differential therebetween as the web roll increases in size, and power dissipation remains unabated.

' The present invention efiectively eliminates each of these critical deficiencies by providing a novel winding mechanism which includes a species of the unique adjustable drive unit disclosed inmy co-pending application Ser. No. 536,459 filed September 26, 1955, and now abandoned. This mechanism does not rely on any form of power dissipating device to maintain a speed differential. Hence, with the exception of unavoidable frictional and inertial power losses, all power supplied by the driving motor is expended exclusively on the web roll being wound. Furthermore, positive infinitely variable speed changing means are incorporated to vary the winding roll speed differential during the Winding operation, but in such a manner that a small, low capacity speed changing unit can easily serve the purpose.

In the mechanism of this invention, a motor drives a pair of winding rolls which are adapted to support the web roll as it is wound. One of the winding rolls is' driven at a positive constant speed substantially directly by the motor while the other is driven at a variable speed through a differential gear unit. The difierential gear unit has positive speed changing means associated therewith, which is adapted to accurately and positively control the speed of the winding roll driven thereby. The speed changing means withdraws from the differential gear unit only a relatively small portion of the total power directed therethrough to the winding roll, and

after the speed change or control is effected it redirects substantially all of the withdrawn power to the winding roll drive. Hence, the speed differential between the pair of Winding rolls may be controlled and varied by controlling the speed function of only a small portion of the total power delivered to one of the winding rolls. Furthermore, this small portion of power so controlled is subsequently recombined with the remainder of the power from which it was withdrawn, and the aggregate is redirected undiminished to the winding roll.

Means are provided in conjunction with the speed changing means to automatically vary the speed ratio across the-latter in response to the continuously increasing size and diameter of the Web roll being wound. Consequently, the speed of the winding roll driven through the differential unit may be infinitely varied, and the relative speed differential between the winding roll may be automatically controlled and varied thereby, as desired.

The differential gear unit and speed changing means are preferably associated with the faster of the two winding rolls, though they could function effectively on the slower roll. Initially in the winding operation the speed differential is at a maximum and substantially all Web tension results from the tangential force exerted on the web by the faster roll. At this point the faster roll may slip slightly against the web. As the web roll grows in size, however, its increasing weight tends to settle or ride more on the faster roll, eliminating any such slippage, and increasing web tension. This tendency toward an increase in tension may be accommodated, however, by reducing the speed of the faster roll through the response of the speed changer to the increasing diameter of the web roll.

Since both winding rolls are positively driven even while the speed of the faster roll is being varied, neither unexpected nor anticipated load changes will affect their respective speeds. In fact, as is disclosed in my aforementioned co-pending application, the adjustable drive unit incorporated herein has the particular ability to maintain its predetermined output speed regardless of variations in load.

It is most desirable to obtain rolls of controlled diminishing density from core to outside, but in practice it has been the fact that the rolls are of uniform hardness from center to periphery or even of progressively increasing hardness from core to periphery. However, when paper rolls of the latter type are stored subsequent to winding, moisture is often absorbed by the paper and some degree of expansion occurs, and occasionally the outer turns of the paper are so stressed by such expansion that they rupture and the roll or a substantial portion of the paper thereof must be discarded. In order to accommodate this effect of moisture absorption, the present apparatus may be operated to wind the inner portion of web in the roll to greater hardness than the outer portion thereof. This is accomplished by correlating the varying speed differential between the winding rolls with the increasing size of the web roll, so that the Patented sept. 19, 1961 w web tension in the roll is greater when the inner turns are applied than when the outer turns are applied.

The inventive features of this novel winding mechanism are more clearly disclosed in the following detailed description of a preferred embodiment thereof. This description refers to the accompanying drawings, wherein:

FIGURE 1 is a diagrammatic perspective view of the winding mechanism;

FIGURE 2 is a partially diagrammatic plan view showing in more detail the drive for the pair of winding rolls;

FIGURE 3 illustrates diagrammatically one method of directing the web about the Winding rolls to the web roll being wound; and

FIGURE 4 illustrates another method of doing the same.

Referring first to FIGURE 1, a pair of parallel. horizontal winding rolls 1 and 2 are rotated in the same direction as indicated, thus imparting counter-rotation to a web roll 3 supported thereby. As a result the web 4 is drawn from a rotatably mounted supply roll 5 (usually being slit and/or trimmed by conventional means which are not shown), passed over the winding roll 2 as shown (or see FIGURE 4 in which it is passed over both rolls 1 and 2), and wound in successive layers about a core shaft 6. In view of the high speeds at which the web roll 3 is wound, it is advisable to include some form of braking means (not shown) on the supply roll 5 so that it does not run ahead of the Web roll when the latter is declerated at the end of the winding operation. Such a braking means may be a conventional single unit combination of motor and generator from which the power required to accelerate the roll is applied by the combination acting as a motor and when the proper point is reached the combination automatically shifts over to act as a generator and thus produces tension in the sheet. The winding rolls 1 and 2 are driven by electric motor 7 (or any other convenient source of power) through a drive shaft 8, and a flexible coupling 9 is included in the drive shaft to transmit driving power from the motor to the winding mechanism. The winding roll 2 is driven substantially directly by the drive shaft 3, while the other winding roll is driven through a positive variable speed drive unit 10. Apinion 11 and a spur gear 12 transfer power from the drive shaft 8 to an input shaft 13 leading into the positive drive unit 10. Output shaft 14 carries the power from the positive variable speed drive unit to the winding roll 1.

FIGURE 2 (with elements somewhat rearranged for clarity) illustrates more clearly the drive unit 10 through which winding roll 1 is driven. The input shaft 13 is directed into a differential gear unit 15 Where it is affixed to input gear 16. A follower gear 17 fixedly mounted on shaft 18 is coaxially opposed to this input gear. The output of the differential gear unit comprises an output gear assembly which engages both the input gear 16 and the follower gear 17. The output gear assembly includes opposed coaxial gears 19 and 2t) rotatably mounted and axially relatively (to each other) fixed upon a shaft 21 supported for limited axial movement in a cage 23 enclosing the differential gear unit. Also included in the planetary output gear assembly are sprocket 24 and spur gear 25 fixedly attached to opposite ends of cage 23. Spur gear 25 engages another spur gear 26 afiixed to output shaft 14 which is connected directly or through a coupling (not shown) to winding roll 1.

Secured fixedly to shaft 18 is a sprocket 2.7 which, of course, rotates along with the follower gear 17. A positive drive chain or belt 2% transfers power between sprocket 27 and sprocket Z9. Sprocket 29 is mounted upon one shaft of a positive infinitely variable speed changing unit 3%. The opposite shaft of the unit 3i? has a sprocket 31 affixed thereto which engages another positive drive chain 32 and chain 32 in turn is operatively connected to the sprocket 24 of the output gear assembly. The positive infinitely variable speed changing unit herein incorporated may be any conventional unit of the 5 form described in my aforementioned co-pending application (eg., a P.I.V. variable speed drive manufactured by the Link-Belt Company). A positive infinitely variable unit of the general type which may be used has also been disclosed in the patent to Trofimov Patent No. 2,555,016 which issued on May 29, 1951. However, an electric motor 33 is included on the unit here to automatically vary the speed ratio between the sprockets 29 and 31. It is to be noted that in order to simplify FIGURE 2, the speed changing unit 30 is shown positioned alongside the differential gear unit 15 rather than directly above it as in FIGURE 1.

Returning now to FIGURE 1 it will be seen that as the web roll 3 increases in size, the core shaft 6 moves upwardly. Electromechanical means are provided, according to this invention, which respond to this upward movement of the core shaft 6 to excite motor 33. Accordingly, adjustment of the speed changing unit 30 is controlled by the increasing diameter of the Web roll 3 being wound.

An endless belt 35 is provided to extend across the drive side of the winding mechanism with one flight along the path of movement of core shaft 6. Pulleys 34 and 36 support the belt and the adjacent end of core shaft 6 is adapted to operatively engage it. Consequently, as core shaft 6 moves upwardly during the increase in diameter of the web roll 3, it causes belt 35 to travel and thus rotate pulleys 34 and 36. Pulley 36 is attached to a shaft 37 which when rotated actuates a potentiometer transmitter 38. Through an electrical circuit which includes an automatic electronic control 39, signals sent by the potentiometer transmitter 38 are received by a potentiometer follower dil. As a result, potentiometer follower 40 is excited, thereby effecting a variation in the current supplied to motor 33. It will be seem therefore, that as the web roll 3 increases in size the speed ratio across the unit 30 may be varied as desired.

Referring now to FIGURES 3 and 4, two methods of directing the web about the winding rolls to the web roll are shown. As discussed hereinbefore, one of the web rolls is to be driven at a speed greater than the other in order to impose the desired tension upon the web as it is wound. Hence, in FIGURE 3 the web 4 is directed under and partially around the first winding roll it encounters, namely winding roll 2, and is immediately taken therefrom to be wrapped about the web roll 3. In this case, winding roll 1 is driven at a faster speed than winding roll 2. Note that the method of FIGURE 3 is the same as that illustrated in FIGURE 1, and the differential gear unit and speed changing means are incorporated with the faster winding roll 1. In FIGURE 4 the web passes under Winding roll 2 and proceeds across to and partially around winding roll 1, and thence to the web roll 3. Since winding roll 2 is now driven at the greater speed, it is preferable that the diiferential gear unit and speed changing means be associated with winding roll 2 rather than with winding roll I.

The operation of this novel winding mechanism is as follows:

A web supply roll 5 may, for example, be positioned adjacent the mechanism, and the web 4 is drawn therefrom to the winding rolls. The end of the web is afiixed by any conventional means to the core shaft 6 and the core shaft is operatively engaged with belt 35. (This engagement of course is such as to accommodate free rotation of the web roll supporting portion of the core shaft.) input gear ltrotates as shown in FIGURE 2, causing gears j and 20 to rotate in opposite directions, thus revolving cage 23 in the same direction as input gear 16. Through spur gears and 2s winding roll 1 is rotated in the same direction as Winding roll 2.

However, a small portion of power is diverted from cage 23 through sprocket 24 and chain 32 to the sprocket 3i. of the speed changing unit 30. The speed function of this small portion of the power is placed under variable positive control in the unit 3%, and the controlled power is subsequently redirected to follower gear 17 of the differential gear unit through sprocket 29, chain 28, and sprocket 27. It is well known that by controlling the speed of the follower gear 17, the speed of the cage 23 may be controlled. Hence speed changing means 30 imposes infinitely variable positive control upon the speed of winding roll 1. Furthermore, since winding roll 2 is also driven positively, the speed ratio between the winding rolls is under complete control and is insensitive to load changes.

As discussed hereinbefore, it is necessary to change the speed ratio of the winding rolls as the web roll 3 increases in size, in order to maintain the desired tension in the Web 4. Therefore, the potentiometers 38 and 40 and the automatic electronic control 39, under the control of belt 35, are adjusted so that motor 33 changes the speed ratio across unit 30 at a rate effecting the desired change in the speed of winding roll 1. By this adjustment the speed of winding roll 1 may for example be made to approach or differ more greatly from the speed of winding roll 2.

It is apparent that certain modifications may be made to the apparatus herein described without departing from the scope of the invention. Therefore it is not intended that the scope of this invention be limited to this illustrated embodiment, but rather only to the extent set forth in the accompanying claims.

I claim:

1. In a web roll winding mechanism comprising a motor, a pair of parallel winding rolls driven by said motor, said winding rolls being adapted to support said web roll as it is wound, one of said winding rolls being driven substantially directly by said motor, the other of said winding rolls being driven through a differential gear unit at a speed different from the speed of said first mentioned winding roll, said differential gear unit having an input gear driven substantially directly by said motor, a follower gear opposed to said input gear, and an interconnecting output gear assembly from which said second mentioned winding roll is substantially directly driven, the improvement comprising positively infinitely variable speed changing means, the input thereof being connected to said follower gear for applying a load thereto, the output of said speed changing means being connected directly to the output of said differential gear unit, and means responsive to the increasing diameter of said web roll being wound for controlling said speed changing means whereby the speed of said second mentioned winding roll may be varied relative to the speed of said first mentioned roll as the web roll being Wound increases in size.

2. A web roll winding mechanism comprising a motor,

a pair of winding rolls driven by said motor, said winding rolls being adapted to support said web roll as it is wound, one of said winding rolls being driven substantially directly by said motor, the other of said winding rolls being driven through a differential gear unit at a speed normally different from the speed of said one winding roll, said differential gear unit having an input gear driven substantially directly by said motor and an output gear from which said other winding roll is driven, the improvement comprising an input to a positive speed changing means for applying a load to a portion of said difierential gear unit to vary the output speed of said unit and said other winding roll, the output of said speed changing means being transmitted directly to the output gear of said difierential gear unit, and means responsive to the increasing diameter of said web roll for controlling said speed changing means whereby the speed of said other winding roll may be varied relative to the speed of said one winding roll as the web roll increases in size.

3. A web roll winding mechanism according to claim 2 wherein said speed changing means is infinitely variable and said means responsive to the increasing diameter of said web roll controls said speed changing means to cause the speed of said other winding roll to approach the speed of said one winding roll in response to the increasing diameter of said roll being wound.

4. A web roll winding mechanism according to claim 1 wherein said interconnecting output gear assembly comprises two intermediate coaxially opposed gears in mesh with said input and follower gears, a shaft mounting said intermediate gears along an axis perpendicular to the axis of said input and follower gears, a cage supporting said shaft for rotation of said shaft therein, means supporting said cage for rotation relative to said input and follower gears and means connecting said cage to drive said second mentioned winding roll.

References Cited in the file of this patent UNITED STATES PATENTS 947,344 Nicholson Ian. 25, 1910 1,266,942 Henderson May 21, 1918 1,663,493 Clay Mar. 20, 1928 2,043,208 Bohn June 2, 1936 2,521,691 Corlett Sept. 12, 1950 2,555,016 Trofimov May 29, 1951 2,858,997 Rockstrom Nov. 4, 1958 2,890,000 Beachler June 9, 1959 2,916,227 Bowen Dec. 8, 1959 

